1. Field of the Invention
The present invention relates to an organic EL display device and a method of manufacturing the organic EL display device, and more specifically, to an organic EL display device that performs display by emitting light on a light emitting element which is a self-luminous body disposed in each pixel, and a method of manufacturing the same.
2. Description of the Related Art
In recent years, an image display device (hereinafter, referred to as “organic EL (Electro-luminescent) display device”) using a self-luminous body called organic light emitting diode (OLED) is in practical use. Since the organic EL display device uses the self-luminous body, it is not only excellent in terms of visibility and response speed, but it is also possible to make the device thinner because an auxiliary illuminating device such as a backlight is not required, compared to a liquid crystal display in the related art.
In a display device in which light is emitted to a side on which a light emitting element of an insulated substrate is formed, that is, a top emission type display device, among an upper electrode and a lower electrode as two electrodes that sandwich an organic layer having at least a light emitting layer as a layer, the upper electrode is an electrode, which covers the entire surface of a display region on which the organic layer is formed, and is formed of a transparent conductive material. It is desired that the upper electrode be formed thinner in order to improve transmittance of light. However, the thinner the upper electrode is, the higher the resistance value is and the lower the voltage is. Therefore, luminance unevenness easily occurs at the end portion and the center of the display region.
JP 2004-207217 A discloses that an upper electrode is brought into contact with an auxiliary electrode in a layer which is the same as that of a lower electrode within a display region, through a connection hole and that the resistance of the upper electrode is reduced. JP 2011-221203 A discloses that an upper electrode is electrically connected to a conductive substrate through a connection hole within a display region.